nRF52 DK improper GPIOTE --> PPI configuration (no interrupts being raised on input toggle)

RE: nRF52 DK improper GPIOTE --> PPI configuration (no interrupts being raised on input toggle)

Dmitry — Mon, 15 Apr 2019 06:03:08 GMT

You're trying to receive analog signal on digital input. It shouldn't be done such way. GPIO expects digital signal in range 0...VDD. For analog signal, configure pin as analog input and use COMP instead of GPIO. In any case input level should be in range 0...VDD, otherwise you need external schematic to ensure that.

Try to connect your pin to GND then VDD, if there's no change in read value, your chip rather didn't withstand 6.6v input.

RE: nRF52 DK improper GPIOTE --> PPI configuration (no interrupts being raised on input toggle)

r_malito — Sun, 14 Apr 2019 21:47:57 GMT

In main.c for loop: NRF_LOG_INFO("PIN_IN value: %i",nrf_gpio_pin_read(PIN_IN))

Pin read on PIN_IN is always 1 if configured as nrf_gpio_cfg_input(PIN_IN, NRF_GPIO_PIN_PULLUP);

Pin read on PIN_IN is always 0 if configured as nrf_gpio_cfg_input(PIN_IN, NRF_GPIO_PIN_PULLDOWN);

Pin read on PIN_IN is always 0 if configured as nrf_gpio_cfg_input(PIN_IN, NRF_GPIO_PIN_NOPULL);

This seems to point to me having my waveform generator input signal incorrectly configured???

I'm also printing my queue size in main as well to see if anything ever gets queued. Its always 0 as well.

RE: nRF52 DK improper GPIOTE --> PPI configuration (no interrupts being raised on input toggle)

Dmitry — Sun, 14 Apr 2019 20:06:34 GMT

I don't think supplying pin with 6.6v is a good idea :)

Can you also print input value (nrf_gpio_pin_read(PIN_IN)) with RTT?

RE: nRF52 DK improper GPIOTE --> PPI configuration (no interrupts being raised on input toggle)

r_malito — Sun, 14 Apr 2019 01:30:49 GMT

I do not believe my GPIOTE_IRQHandler function is ever being called. My RTT log never contains the line from the handler:

NRF_LOG_INFO("in GPIOTE_IRQHandler...");

When I was first building the project, the function definition for GPIOTE_IRQHandler() was getting an error because it was claiming to be already defined in nrfx_gpiote.c (line 668) as void nrfx_gpiote_irq_handler(void).

I commented this function out as that is what I saw people saying to do in DevZone question answers.

I'm not sure if that could be causing my handler to not be called every polarity toggle on the input pin.

I have tried various input signal settings with a function generator. None seem to trigger the handler:

Frequencies Tested: 1 Hz to 1000 Hz

Polarities tested: normal & inverted

----------------------

Specific Setting Combinations tried to trigger event:

----------------------

Amplitude (6.6v pk-pk)

Load type: Hi-Z (High Impedance)

----------------------

Amplitude (3.3v pk-pk)

Load type: 50 Ohm resistance

---------------------

Amplitude (3.3v pk-pk)

Offset: 1.65v (in effort to get clear distinction between high and low)

Load type: 50 Ohm resistance

RE: nRF52 DK improper GPIOTE --> PPI configuration (no interrupts being raised on input toggle)

Dmitry — Sat, 13 Apr 2019 23:27:53 GMT

You're clearing EVENTS_IN[1] in interrupt handler, so you will always see 0 in main thread. In general your code is correct. Does your GPIOTE_IRQHandler get called?

What input signal do you have - push-pull or open-drain?

RE: nRF52 DK improper GPIOTE --> PPI configuration (no interrupts being raised on input toggle)

r_malito — Sat, 13 Apr 2019 04:49:37 GMT

NRF_GPIOTE->EVENTS_IN[1] is always 0 (pardon my typo) (I can answer any other intermediate questions that viewers of this post have as well in order to facilitate a solution!)